Various insulation materials, in which a coating has been joined to a porous insulation layer, are applied in construction technology. The coating can be used to improve the insulating properties, durability, fire safety, dimensional stability, or the appearance of the material.
Aluminum foil is often used in the coatings of insulation materials. It is impermeable to gases and is incombustible, and reflects thermal radiation. The aluminum foil is joined to the insulation layer by means of a plastic adhesion layer. The insulation material is manufactured in the following manner: firstly, the adhesion layer is joined to the aluminum sheet, after which the laminate that has thus been produced is joined to the insulation layer. This can be done, for example, with polyurethane while it is still in a reactive state, whereby the layers self-adhere without separate gluing. When there is a gas-tight aluminum layer against the layer of cellular plastic, the propellants in the cellular plastic remain inside it to an optimal degree.
One problem here is, however, the insufficient strength of the coating during the manufacture of the insulation material. The aluminum sheet is easily torn when it is pulled into the machine. For example, during the coating of a polyurethane insulation that is still forming, failures are particularly harmful, as the expanding polyurethane foam is spread and stains the production machinery and floor. In fact, the primary function of the coating in such a situation is to protect the process machinery from reactive and sticky insulation material in the initial phase of the process.